Lifting-jack.



WITNESSES J. R. LOWRY.

LIFTING JACK.

APPLICATION FILED MAR. 7, 1917.

Patented Dec. 18,1912

g INVENTOR UNITED STATES PATENT oFFIoE.

JEFFERSON B. LOWRY, OE MEMPHIS, TENNESSEE. I I

LIFTING-J'ACK.

Specification of Letters Patent. Patented Dec. 18, 191 7 Application filed March 7, 1917. Serial No. 153,111.

To all whom it may concern:

Be it known that I, JEFFERSON R. LowRY, a citizen of the UnitedStates, residing at Memphis, in the countv of Shelby and State of Tennessee, have invented new and useful Improvements in Lifting-Jacks, of which the following is a specification. I

My invention relates to lifting jacks and has for its object; first, to provide a lifting jack of light and convenient size which may be attached to a longitudinal support of regular cross section disposed parallel to the direction of stress, second, to provide a lifting jack which is'readily'and quickly adjustable along a support of regular cross section running parallel to the direction of stress, and thirdly, to provide a lifting jack readily adjustable along a longitudinal support of regular cross section running parallel to the lifting strain adapted to automatically clamp at any point on said support.

I attain these objects by the mechanism illustrated in the accompanying drawings forming a part of this specification in which Figure 1 is a front view of the lifting jack in working relation to a load.

Fig. 2 is a top plan viewin partial section of the device.

Fig. 3 is an enlarged partial side view of a portion of the mechanism.

Like characters of reference indicate like" parts in the various views.

In the drawings 1 designates supports which are of regular cross section and are disposed substantially parallel to each other and to the line of strain. These supports are held in position in any approved way and inasmuch as the means for positioning them does not enter into my invention a description of the same is unnecessary to an understanding of my invention. A base plate A is formed of the two castings 2 clamped together by the bolts 3. On each casting of said base plate A is disposed a downwardly extending ear 4. A pivot pin 5 is disposed upon said pair of ears 4 adjacent either end thereof and at a substantially right angle to the supports 1. Tilting levers 6 have outwardly extending arms 7, at the ends of which are formed vertical holes or inclosures 8. Said holes or inclosures 8 engage supports 1 and are fitted loosel thereto for purposes hereinafter deseri Tilt= ing levers 6 have inwardly extending arms 9 so disposed" thatthey extend-toward each other under the base plate A and almost meet. A compression spring 10 is disposed between the under surface of the baseplate A and the'ends of said arms 9 whereby the levers 6 tend toassume a downwardly tilted position. Projections 11 upon arms 9 and a projection 12'upon the under surface of base plate A serve to retain spring 10 in a proper working position. I

At the center of base plate A is a spherical recess 13 having an opening at the top and formed at the jointure of castings 2 by coincident hemisphericaldepressions in said castings 2. A jack screw 14 engages said recess 13 with its lower end which is sphericalin form. Said jack screw extends upwardly having threads 15 formed upon its cylindrical surface and terminates in a head 16 which is adapted to engage a wrench of usual construction. A screw plate 17 engages the threads 15 of screw 14. Abeam 18 is affixed to the upper surface of plate 17, i

said beam having an aperture through which jack screw 14 extends. The load 20' is engaged by the ends of beam 18 in such a manner that the head 16 of ack properly manipulated.

The spring 10 pushes the tilting levers in a 'downwardly tilt-ed position and clamps them upon their respective supports 1 by the loose engagement of holes or inclcsmes 8 with said supports. This downwardly tilted or clamping position prevents any downward movement of the base plate A by means of the initial clamping eii ect of spring 10 and the increased clamping effect of an downward stress placed upon base plate K and transmitted to said levers 6 through pivot pins 5.

It will be noted that while spring 10 holds levers 6 in an initial clamping position respecting downward movement the position of levers 6 allows the device to be moved upward respecting supports 1 without interference. To move the device downwardly upon supports 1, levers (i are manually tilted against spring 10 to a position at which there is no clamping action of holes or in closures 8 upon supports 1.

It will be noted that though the inclosures 8 are shown as holes in the drawings it is not necessary that supports 1 be completely screw 14. may beencircled by said inc closures. It is sufficient if there be a substantial bearing of said in closures upon supports 1 at the far and near side of the support respecting pivot pins 5, so that the clamping action niay be effected.

In the operation of the device the base plate A and appended parts are moved along supports 1 in the manner hereinbefore described until the device is in proper relation with the load. The jacksorew 14, is then maniplated to lift the load through threaded Plate 1 an "18- H ving t us ful y de cribed ll -y inven ion, I e aim 1. In a support, a beseplate comprising w ebu ng m mbers ecured together, a downwardly extending ear on each'member, horizontally disposedpivot pins mounted on said cars, a lever pivoted a point intermediate the e dsthereof to re pective pi o pins and havingvertically disposed incloures formed at the outer ends thereof, the er ends thereofeatending toward each r, d a singl i-sp ing m ans engaging the inner ends 'of'said ljeversad adapted to norma y r ta n sa d. lever in afilted positi n rela i to aiclba e- 2. In a.support,a-base plate comprising two abutting members secured --together-, a downwardly extending. earon each member, ori on ally dispose pivo 7 pins m un e in said ears, a le er pivoted at a p in i e me iate th ndsther f torespective pi ot p ns. and ha i g ve ti al y disposed inc esures formed at the outer ends thereof, the inner ends thereof ex en ing-to rd each other and having upwgzrdlyextending lugs rmed the e n, a dewnwardly extend g 1 g fo ed aid ase, and; aeeiled com- Pression p g p sed between said inn saidears and-having vertically disposed inclosures formed at the outer ends thereof, the inner ends thereof extending toward each other, and a single spring means engaging the inner ends of said levers and adapted to normally retain said levers in a tilted position relative to said base.

, .4. In a support, a base plate comprising two abutting members having coincident hemispherical depressions on the abutting surfaces thereof and secured together, a

jack screw having its lower end journaled therein, a downwardly extending car on each member, horizontally disposed pivot pins mounted on said ears, a lever pivoted at a point intermediate theends thereof to respective pivot pins and having vertically disposed inclosures formedat the outer ends thereof, the inner ends thereof extending to.- ward each other andhaving upwardly extending lugs formed on said inner ends, a downwardy extending lug for-med on said base and disposed abovesaid first mentioned lugs, and a coiled compression spring disposed between the base and the inner ends of said levers andengaging said'lugs.

Intestimony whereof I afiix my signature.

JEFFERSON R. LOWRY.

C pies 0! thispatent pgyheeobtsinqdJerome cents each, by addressing the Commissioner of Patents, ashi on), D- Q 

